Sandboxing Against Supply Chain Worms: How Ringfence Blocks Secret Theft from npm Dependencies

The May 2026 'Shai-Hulud' supply chain attack exposed how npm postinstall scripts can steal secrets with unrestricted filesystem access, compromising 84 packages despite valid provenance. Ringfence addresses this vulnerability by sandboxing package manager operations at the OS level, rendering secrets invisible to compromised code without blocking installation. This represents a paradigm shift: rather than trying to prevent malicious code, the tool limits what that code can access—a critical safeguard for build pipeline security.